Preheat oven to 350 °F (175 °C). Line baking sheets with parchment paper.

In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.

Add eggs one at a time, mixing well after each. Stir in vanilla extract until combined.

In a separate bowl, whisk together the flour, baking soda, salt, and cornstarch. Gradually add to the wet ingredients, mixing until just incorporated.

Stir in the white chocolate chips.

Take a portion of dough (about 2–3 Tbsp), flatten it slightly, place a piece or chunk of white chocolate in the center, and wrap the dough around it fully so the chocolate is sealed inside. Repeat for remaining dough.

Place the stuffed dough balls on the prepared baking sheets, spacing them a couple inches apart.

Bake 10–12 minutes, until the edges are set but centers still look slightly underdone.

Let the cookies cool on the baking sheet 5–7 minutes — this helps the gooey center stay intact — then transfer to a cooling rack.